1. Field of the Invention
The present invention relates to a shock absorber, and particularly to a shock absorber mounted in a storage box or packaging box.
2. Description of the Related Art
A corrugated cardboard cushion has been used to moderate damages to a product due to falling of a packaging box or storage box when the product is distributed while accommodated in the packaging or storage box.
FIG. 1 is a perspective view showing a conventional corrugated cardboard cushion.
The corrugated cardboard cushion comprises a flat face portion 101 for supporting a product (not shown), and side face portions 103, 105 linked to both the sides of the flat face portion 101. When a projecting portion of the product interferes in (locally abuts against) the flat face portion 101, holes 107, 109, for example, are formed in the flat face portion 101 to avoid such interference. When an external force is applied to the product in a direction indicated by an arrow in FIG. 1, the flat face portion 101 of the corrugated cardboard cushion is folded in accordance with the external force, whereby the corrugated cardboard cushion exhibits its shock absorption effect.
FIG. 2(A) is a perspective view showing another conventional corrugated cardboard cushion, and FIG. 2(B) is an exploded perspective view of the corrugated cardboard cushion of FIG. 2(A). The corrugated cardboard cushion shown in FIGS. 2(A) and 2(B) comprises a flat face portion 101 on which a product (not shown) is put, side face portions 103, 105 linked to both the sides of the flat face portion 101, and side face portion 111 and 113 which are perpendicularly linked to each of the flat face portion 101 and the side face portions 103 and 105, the side face portions 111 and 113 having linear end portions 111a and 113a on which the product is actually put. When an external force is applied to the product in an direction indicated by an arrow in FIG. 2(A), the side face portions 111, 113 having the linear end portions 111a, 113a are crushed, thereby exhibiting a shock absorption effect.
In the corrugated cardboard cushion shown in FIG. 1 and other conventional similar corrugated cardboard cushions, the product is supported on the flat face portion 101 of the cushion while the projecting portions of the product are inserted into the holes 107, 109 to avoid the interface (local abutting), thereby exhibiting the shock absorption effect on the product. Therefore, when a product having a number of projecting portions is mounted on such a corrugated cardboard cushion, the number of clearance portions such as holes or the like is increased, so that it is difficult to exhibit the shock absorption effect.
In the corrugated cardboard cushion shown in FIGS. 2(A) and 2(B) and other conventional similar corrugated cardboard cushions, when an external force is applied to a product, the side face portions 111, 113 having the linear end portions 111a, 113a are crushed, thereby exhibiting the shock absorption effect on the product. However, it is difficult to crush the linear end portions (113a, 113b, 111a, 111b) stably, so that dispersion of the absorption effect is liable to occur.
FIG. 3(A) is a cross-sectional view showing a part of an arrangement of a corrugated cardboard cushion and a product when the product is put on the side face portions having linear end portions of the cushion. FIG. 3(B) is a cross-sectional view showing a state where the side face portions are ideally crushed due to an external force applied to the product shown in FIG. 3(A), whereby the cushion exhibits a shock absorption effect on the product. FIG. 3(C) is a cross-sectional view showing a state where the side face portions tilt and fall due to an external force applied on the product and thus no shock absorption effect is exhibited on the product.
As shown in FIG. 3(B), for example when an external force is applied to a product 115 due to falling of a packaging box or the like, the sufficient shock absorption effect could be exhibited if the side face portions 113 are crushed in parallel to the side faces thereof. However, in many cases, the side face portions 113 tilt and fall as shown in FIG. 3(C) and thus no sufficient shock absorption effect is exhibited.